Subspecies
Of the following four subspecies described in the literature, only the first two (B. b. blakistoni & B. b. doerriesi) are currently accepted by science (Slaght and Surmach 2008). The other two (B. b. karafutonis and B. b. piscivorus) were likely specimens of B. b. blakistoni & B. b. doerriesi, respectively, and are presented here only for historical interest.
B. b. blakistoni (Seebohm, 1884). Hokkaido, N. Japan and Kuriles. Lores of facial disc tawny-brown with narrow black shaft-stripes; above eyes, around bill base and on forehead a row small, stiff almost completely white feathers; chin largely white. Rest of head and underparts brown with blackish-brown shaft-stripes and buff feather tips; back is darker. The mantle is somewhat lighter and more rufous and with blackish-brown bars as well as dark brown shaft-streaks. Wings deep brown with numerous buffy-yellow bars. Tail dark brown with 7-8 cream-yellow bars. Underparts light buff-brown with blackish-brown shaft streaks and narrow light brown wavy cross-bars.
B. b. doerriesi (Seebohm, 1884). E. Siberia south to Vladivostok region and Korean border area. Larger than nominate with large white patch on top of the head; tail less marked and bars incomplete.
B. b. karafutonis (Kuroda, 1931). Sakhalin. Smaller than nominate race and darker, especially on back and ear-coverts; tail with narrower dark brown bars and the light bars more numerous (8-9 against 7 in nominate).
B. b. piscivorus (Meise, 1933). W. Manchuria. Paler overall than doerriesi, ground color of underparts grayish-white (not buff-brown); tail-bars not fully creamy-yellow, central rectrices having white inner webs almost to base; chin pure white.
Read more about this topic: Blakiston's Fish Owl